When I produce pdf file by dvi->ps->pdf method TXC applies the command "dvips -P pdf filename.dvi".
Then the following happens: dvips starts and reads configuration file config.pdf.
In my MikTex distribution this file is in the miktex2.9/dvips/tetex folder (it has been installed there by the miktex installation program).
The file config.pdf contains line "D 8000" that demands dvips to produce fonts at 8000dpi resolution (not 600 as usual).
The comment near this line explains that the idea of this huge number is to make tetex resolution independent or something like this.
Probably,TXC should work independently of these strange ideas.